Aqueous cleaning composition containing copper-specific corrosion inhibitor for cleaning inorganic residues on semiconductor substrate

ABSTRACT

A semiconductor wafer cleaning formulation, including 1-35% wt. fluoride source, 20-60% wt. organic amine(s), 0.1-40% wt. nitrogenous component, e.g., a nitrogen-containing carboxylic acid or an imine, 20-50% wt. water, and 0-21% wt. metal chelating agent(s). The formulations are useful to remove residue from wafers following a resist plasma ashing step, such as inorganic residue from semiconductor wafers containing delicate copper interconnecting structures.

RELATED APPLICATIONS

This application claims the benefit of U.S. patent application Ser. No.09/818,073 filed Mar. 3, 2001 which in turn claims priority of U.S.patent application Ser. No. 08/924,021 filed on Aug. 29, 1997, which inturn claims the priority of U.S. Provisional Patent Application60/044,824 filed Apr. 25, 1997 and U.S. Provisional Patent Application60/034,194 filed Jan. 9, 1997. Additionally, this application claimspriority to and repeats a substantial portion of prior U.S. patentapplication Ser. No. 09/818,073 filed Mar. 3, 2001 and U.S. patentapplication Ser. No. 08/924,021 filed on Aug. 29, 1997. Since thisapplication names an inventor named in the prior application, theapplication constitutes a continuation in part of the prior application.This application incorporates by reference prior U.S. patent applicationSer. No. 09/818,073 filed Mar. 3, 2001, U.S. patent application Ser. No.08/924,021 filed on Aug. 29, 1997, U.S. Provisional Patent Application60/044,824 filed on Apr. 25, 1997 and U.S. Provisional PatentApplication 60/034,194 filed on Jan. 9, 1997.

FIELD OF THE INVENTION

The present invention relates generally to chemical formulations usefulin semiconductor manufacturing and particularly to chemical formulationsthat are utilized to remove residue from wafers following a resistplasma ashing step. More specifically, the present invention relates tocleaning formulations for removal of inorganic residue fromsemiconductor wafers containing delicate copper interconnectingstructures.

DESCRIPTION OF THE PRIOR ART

The prior art teaches the utilization of various chemical formulationsto remove residues and clean wafers following a resist ashing step. Someof these prior art chemical formulations include alkaline compositionscontaining amines and/or tetraalkyl ammonium hydroxides, water and/orother solvents, and chelating agents. Still other formulations are basedon acidic to neutral solutions containing ammonium fluoride.

The various prior art formulations have drawbacks that include unwantedremoval of metal or insulator layers and the corrosion of desirablemetal layers, particularly copper or copper alloys features. Some priorart formulations employ corrosion inhibiting additives to preventundesirable copper metal corrosion during the cleaning process. However,conventional corrosion-inhibiting additives typically have detrimentaleffects on the cleaning process because such additives interact with theresidue and inhibit dissolution of such residue into the cleaning fluid.Moreover, conventional additives do not easily rinse off the coppersurface after completion of the cleaning process. Such additivestherefore remain on the surface sought to be cleaned, and result incontamination of the integrated circuits. Contamination of theintegrated circuit can adversely increase the electrical resistance ofcontaminated areas and cause unpredictable conducting failure within thecircuit.

The formulation of post CMP cleaners for advanced integrated circuitmanufacturing such as copper and tungsten interconnect materials,includes slurry removal and residue dissolution components thataccelerate the physical cleaning process. However, these conventionaladditives typically have detrimental effects on the metal surface byincreasing resistance and corrosion sensitivity.

It is therefore one object of the present invention to provide chemicalformulations that effectively remove residue following a resist ashingstep, and which do not attack and potentially degrade delicatestructures intended to remain on the wafer.

It is another object of the present invention to replace conventionaladditives with an improved corrosion inhibitor for protection of copperstructures on the semiconductor substrate.

It is another object of the invention to provide an improved corrosioninhibitor, which is easily rinsed off the substrate by water or otherrinse medium after the completion of the residue-removal process,thereby reducing contamination of the integrated circuit.

Other objects and advantages of the invention will become fully apparentfrom the ensuing disclosure and appended claims.

SUMMARY OF THE INVENTION

The present invention relates generally to chemical formulations usefulin semiconductor manufacturing for removing residue from wafersfollowing a resist plasma ashing step.

In one aspect, the invention relates to a method of removing residuefrom a wafer following a resist plasma ashing step on such wafer,comprising contacting the wafer with a cleaning formulation, including(i) a fluoride source, (ii) at least one organic amine, (iii) anitrogen-containing carboxylic acid or an imine, (iv) water, andoptionally at least one metal chelating agent.

Another aspect of the invention relates to a wafer cleaning formulation,including (i) a fluoride source, (ii) at least one organic amine, (iii)a nitrogen-containing carboxylic acid or an imine, (iv) water, andoptionally at least one metal chelating agent.

In a further aspect, the invention relates to a semiconductor wafercleaning formulation for use in post plasma ashing semiconductorfabrication, comprising the following components in the percentage byweight (based on the total weight of the formulation) ranges shown:

a fluoride source, e.g., ammonium fluoride and/or  1-35% derivative(s)thereof organic amine(s) 20-60% a nitrogenous component selected fromnitrogen-containing 0.1-40%  carboxylic acids and imines water 20-50%metal chelating agent(s)  0-21% TOTAL 100%

In a still further aspect, the invention relates to a formulation usefulfor post chemical mechanical polishing (CMP) cleaning, which is a diluteversion of the wafer cleaning formulation outlined hereinabove, whereinthe dilute formulation comprises: (i) a fluoride source, (ii) at leastone organic amine, (iii) 70% to 98% water, and optionally at least onemetal chelating agent and optionally a nitrogen-containing carboxylicacid or an imine.

Such formulations of the invention effectively remove inorganic residuesfollowing a plasma ashing and/or CMP step.

Such formulations also effectively remove metal halide and metal oxideresidues following plasma ashing, and effectively remove slurryparticles of aluminum oxides and other oxides remaining after CMP(chemical mechanical polishing).

The formulations of the present invention provide better strippingperformance with less corrosivity than formulations containing eitherammonium fluoride or amines. Formulations in accordance with theinvention also provide better stripping performance at lower processingtemperatures than conventional amine-containing formulations.

The formulations of the invention utilize a chelating agent, which maybe a single-component chelating agent or a multicomponent-chelatingagent, to prevent metal corrosion and increase stripping effectiveness.

Other features and advantages of the present invention will be from theensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a copper-specific corrosioninhibitor useful in the broad practice of the present invention, whichforms a protective layer on the copper metal to prevent corrosion;

FIG. 2 is a schematic representation of the copper-specific corrosioninhibitor being rinsed away from the copper surface by deionized water;

FIG. 3 depicts cleaning components of the present invention interactingwith a surface;

FIG. 4 illustrates that formulations of the present invention maybe usedto remove residues and particles;

FIG. 5 provides a SEM representing results obtained from an immersionprocess; and

FIG. 6 illustrates the material etch rate on interconnect materials.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The formulations of the present invention are suitable for strippinginorganic wafer residues deriving from high-density plasma etchingfollowed by ashing with oxygen-containing plasmas. Such formulations, indilute form, are also suitable for removing slurry particles of aluminumoxides and other oxides remaining after CMP (chemical mechanicalpolishing).

The formulations advantageously contain (i) a fluoride source, such asammonium fluoride and/or derivative(s) of ammonium fluoride, (ii) anamine or mixture of amines, (iii) a nitrogen-containing carboxylic acidor imine, (iv) water, and, optionally and preferably, (v) one or moremetal chelating agents.

As used herein, a fluoride source refers to a compound or a mixture ofcompounds that in the aqueous cleaning formulation provides fluorineanions.

The preferred formulations for post etch removal include the followingcomponents in the percentage by weight (based on the total weight of theformulation) ranges shown:

fluoride source  1-35% organic amine(s) 20-60% a nitrogenous componentselected from nitrogen containing 0.1-40%  carboxylic acids and imineswater 20-50% metal chelating agent(s)  0-21% TOTAL 100%

The preferred formulations for post CMP cleaning include the followingcomponents in the percentage by weight (based on the total weight of theformulation) ranges shown:

fluoride source 0.1%-5%   organic amine(s)  1%-15% a nitrogenouscomponent selected from nitrogen containing     0-10% carboxylic acidsand imines water 70%-98% metal chelating agent(s)    0-5% TOTAL 100%

The components of the formulation as described above can be of anysuitable type or species, as will be appreciated by those of ordinaryskill in the art. Specific illustrative and preferred formulationcomponents for each of the ingredients of the formulation are describedbelow.

Particularly preferred amines include one or more of the following:

-   diglycolamine (DGA),-   methyldiethanolamine (MDEA),-   pentamethyldiethylenetriamine (PMDETA),-   triethanolamine (TEA), and-   triethylenediamine (TEDA).

Other amines that are highly advantageous include:

-   hexamethylenetetramine,-   3,3-iminobis(N,N-dimethylpropylamine),-   monoethanolamine-   2-(methylamino)ethanol,-   4-(2-hydroxyethyl)morpholine-   4-(3-aminopropyl)morpholine, and-   N,N-dimethyl-2-(2-aminoethoxyl)ethanol.

Fluoride sources useful in the present invention include any combinationof ammonia gas or ammonium hydroxide and hydrogen fluoride gas orhydrofluoric acid. Specific preferred fluoride sources include, but arenot limited to one or more of the following:

-   ammonium fluoride, and-   ammonium bifluoride

Other fluoride sources that are highly advantageous include:

-   triethanolammonium fluoride (TEAF);-   diglycolammonium fluoride (DGAF);-   methyldiethanolammonium fluoride (MDEAF)-   tetramethylammonium fluoride (TMAF); and-   triethylamine tris(hydrogen fluoride) (TREAT-HF).

Specific preferred nitrogen-containing carboxylic acids and iminesinclude one or more of the following:

-   iminodiacetic acid (IDA);-   glycine;-   nitrilotriacetic acid (NTA);-   1,1,3,3-tetramethylguanidine (TMG); and-   hydroxyethyliminodiacetic acid ethylenediaminetetracetic acid    (EDTA).

Other nitrogen-containing carboxylic acids or imines advantageouslyutilizable in formulations of the invention include:

-   CH₃C(═NCH₂CH₂OH)CH₂C(O)N(CH₃)₂-   CH₃C(═NCH₂CH₂OCH₂CH₂OH)CH₂C(O)N(CH₃)₂-   CH₃C(═NH)CH₂C(O)CH₃-   (CH₃CH₂)₂NC(═NH)N(CH₃CH₂)₂-   HOOCCH₂N(CH₃)₂-   HOOCCH₂N(CH₃)CH₂COOH

Specific preferred metal chelating agents include:

-   acetoacetamide;-   ammonium carbamate;-   ammonium pyrrolidinedithiocarbamate (APDC);-   dimethyl malonate;-   methyl acetoacetate;-   N-methyl acetoacetamide;-   2,4-pentanedione;-   tetramethylammonium thiobenzoate;-   1,1,1,5,5,5-hexafluoro-2,4-pentanedione H(hfac);-   2,2,6,6-tetramethyl-3,5-heptanedione H(thd);-   tetramethylammonium trifluoroacetate;-   tetramethylthiuram disulfide (TMTDS);-   trifluoracetic acid;-   lactic acid;-   ammonium lactate;-   malonic acid-   formic acid,-   acetic acid,-   propionic acid,-   gamma-butyrolactone,-   methyldiethanolammonium trifluoroacetate, and-   trifluoroacetic acid.

The combination of ammonium fluoride or a substituted fluoride source,as described above, with an amine (other than an amine present as asurfactant in an amount of 1% or less) provides better strippingperformance with less corrosivity than formulations containing eitherammonium fluoride or amines alone. In addition, the resulting alkalinesolutions are effective at lower processing temperatures (e.g., 21°-40°C.) than conventional amine-containing formulations.

The presence of nitrogen-containing carboxylic acids and/or iminesenables formulations of the invention to be remarkably effective instripping residues from semiconductor substrate surfaces containingdelicate copper structures.

The nitrogen-containing carboxylic acids or imines provide functionalgroups that are specifically attracted to free copper atoms. As shownschematically in FIG. 1, the copper-specific corrosion inhibiting-agentC, which contacts the copper surface during the residue-removal process,will attach to the copper surface and form a protective layer to preventthe copper surface being corroded by cleaning agents A⁺ and X⁻.

Moreover, as shown by FIG. 2, such copper-specific corrosion-inhibitingagent C can be easily rinsed off by deionized water or other solutionsand therefore leaves very little contamination on the copper surfaceafter the cleaning operation.

The use of 1,3-dicarbonyl compounds as chelating agents and to preventmetal corrosion is a preferred feature of the inventive formulations, toincrease their effectiveness.

In various prior art formulations, amines are present in amounts of 1%or less of the formulation as surfactants, or otherwise are not utilizedas formulation ingredients at all. Additionally, the prior artformulations are acidic (pH<7) in character. In preferred formulationsof the present invention, the amines are present as major components ofthe formulation, are highly effective in stripping action, and yieldformulations of a basic pH character (pH>7).

The formulations of the invention may include a wide variety of organicamines, substituted ammonium fluorides, and nitrogen-containingcarboxylic acids, other than those specifically exemplified. Particularsubstituted ammonium fluorides of suitable character include those ofthe general formula, R₁R₂R₃R₄NF in which each of the respective Rspecies is independently selected from hydrogen and aliphatic groups.Suitable nitrogen-containing carboxylic acids include those of thegeneral structure COOH—CH₂—NRR′, wherein R and R′ are each independentlyselected from the group consisting of hydrogen, alkyl, aryl, andcarboxylic acid moieties. Suitable metal chelating agents include1,3-dicarbonyl compounds of the general structure X—CHR—Y. In compoundsof such formula, R is either a hydrogen atom or an aliphatic group,e.g., C₁-C₈ alkyl, aryl, alkenyl, etc. X and Y may be the same as ordifferent from one another, and are functional groups containingmultiply-bonded moieties with electron-withdrawing properties, as forexample CONH₂, CONHR′, CN, NO₂, SOR′, or SO₂Z, in which R′ represents aC₁-C₈ alkyl group and Z represents another atom or group, e.g.,hydrogen, halo or C₁-C₈ alkyl.

Other chelating agent species useful in the compositions of theinvention include amine trifluoroacetates of the general formula,R₁R₂R₃R₄N⁺⁻O₂CCF₃ in which each of the R groups is independentlyselected from hydrogen and aliphatic groups, e.g., C₁-C₈ alkyl, aryl,alkenyl, etc.

The formulations of the invention optionally may also include suchcomponents as surfactants, stabilizers, corrosion inhibitors, bufferingagents, and co-solvents, as useful or desired in a given end useapplication of formulations of the invention.

Formulations in accordance with the present invention are particularlyuseful on wafers that have been etched with chlorine- orfluorine-containing plasmas, followed by oxygen plasma ashing. Theresidues generated by this type of processing typically contain metaloxides. Such residues are often difficult to dissolve completely withoutcausing corrosion of metal and titanium nitride features required foreffective device performance. Also, metal oxide and silicon oxide slurryparticles remaining after CMP will also be effectively removed byformulations in accordance with the present invention.

The features and advantages of the invention are more fully shown by thefollowing non-limiting examples.

Example 1

Copper-specific corrosion inhibitors including eitherhydrogen-containing carboxylic acids or imines were tested in twodifferent types of alkaline cleaning formulations, with the followingcomponents and characteristics.

TABLE 1 Copper Temp., Etch Rate Components ° C. pH (Å/min) Formulation 1dimethylacetoacetamide, 70 6.2 17.4 amine, and water Formulation 2ammonium fluoride, 40 8.6 7.5 triethanolamine,pentamethdiethylenetriamine, and water

The copper etch rate was determined by a standard four-point probetechnique. Addition of corrosion inhibitors in accordance with thepresent invention significantly slowed down the copper etch rate, asshown by the following table, and effectively prevented undesirablecorrosion during the cleaning process:

TABLE 2 Copper Etch Reduction of Temp. Formulation Concentration pH ofRate Etch Rate Corrosion Inhibitor (° C.) Used (%) solution (Å/min) (%)Iminodiacetic Acid 40 2 1.5 8.0 1-2 −73.3~86.7 Glycine 40 2 1.5 9.2 3.6−52.0 Nitrilotriacetic Acid 40 2 1.5 8.2 3.6 −52.01,1,3,3-tetramethylguanidine 40 2 1.5 8.7 3.4 −54.7CH₃C(═NCH₂CH₂OH)CH₂C(O)N(CH₃)₂ 70 1 24 10.9 6.2 −64.4CH₃C(═NCH₂CH₂OCH₂CH₂OH)CH₂C(O)N(CH₃)₂ 70 1 36 10.7 0.32 −98.2CH₃C(═NH)CH₂C(O)CH₃ 40 2 13.68 7.9 4.4 −41.3

Example 2

A contamination test was carried out on Formulation 2 containingiminodiacetic acid inhibitor. The semiconductor wafer to be cleanedcontained copper and silicon films. After the completion of the cleaningoperation, the wafer was rinsed by deionized water at 25° C. for about15 minutes. The Secondary Ion Mass Spectrometry data (SIMS) obtained areas follows:

Cu F C (atoms/cm²) (atoms/cm²) (atoms/cm²) Cu_(x)O (Å) Uncleaned Wafer1.6 × 10¹⁰ 3.3 × 10¹³ 7.5 × 10¹³ 42 Cleaned Wafer 8.5 × 10⁹ 5.1 × 10¹³1.5 × 10¹³ 15

The foregoing results show that the copper oxide Cu_(x)O has beeneffectively removed by the cleaning process, while carbon contamination,which is mainly caused by the organic corrosion inhibitors in thecleaning formulation, has been greatly reduced.

The present invention employs dilute alkaline fluoride in compositionsfor post CMP cleaning of silicon oxide or aluminum oxide particles frommetallic surfaces such as copper or tungsten. FIG. 3 depicts how thecleaning components of the present invention interact with the surface.Specially, FIG. 3 depicts that Alkaline Fluoride 30 and chelating agents32 dissolving inorganic oxide residues 34 after a CMP process.

FIG. 4 illustrates that the formulations taught by the present inventionmay be used to remove residues 40 and particles 42 for a copper surface44. In FIG. 4 particles 42 and residues 40 adhere to metal surface 44 aswell as dielectric surface 46. Particles 42 and residues 40 may remainfollowing a CMP process. The chemical solutions of the present inventiondegrade the attractive forces between the residue and the surface aswell as dissolve copper and tungsten oxides and oxy-halides.

Formulations that have been found to be effective in cleaning residueand slurry particles from metal surfaces may have a pH value in a rangefor from about 3 to 11, but typically have pH values between about 7 andabout 9. These formulations generally are aqueous solutions thatcomprise a fluoride source, an organic amine, and metal chelating agent.The individual constituents typically constitute a fluoride sourceand/or a derivative thereof as about 0.1 to about 5.0% of theformulation, wherein the fluoride may be one of many such fluoridesources known to those skilled in the art including one or more of:

-   any combination of ammonia gas or ammonium hydroxide and hydrogen    fluoride gas or hydrofluoric acid;-   ammonium fluoride,-   ammonium bifluoride;-   triethanolammonium fluoride (TEAF);-   diglycolammonium fluoride (DGAF);-   methyldiethanolammonium fluoride (MDEAF)-   tetramethylammonium fluoride (TMAF);-   triethylamine tris(hydrogen fluoride) (TREAT-HF).

The organic amine or mixture of two amines typically comprises betweenabout 1% and about 15% of the formulation of the present invention,wherein the organic amine can be one of many such organic amines knownto those skilled in the art including:

-   diglycolamine (DGA),-   methyldiethanolamine (MDEA),-   pentamethyldiethylenetriamine (PMDETA),-   triethanolamine (TEA),-   triethylenediamine (TEDA),-   hexamethylenetetramine,-   3,3-iminobis(N,N-dimethylpropylamine),-   monoethanolamine-   2-(methylamino)ethanol,-   4-(2-hydroxyethyl)morpholine-   4-(3-aminopropyl)morpholine, and-   N,N-dimethyl-2-(2-aminoethoxyl)ethanol.

The nitrogenous component of the mixture typically comprises 0 to about10% of the mixture. wherein the nitrogenous component may be one of manysuch nitrogenous component sources known to those skilled in the artincluding one or more of:

-   iminodiacetic acid (IDA),-   glycine,-   nitrilotriacetic acid (NTA),-   hydroxyethyliminodiacetic acid,-   1,1,3,-tetramethylguanidine (TMG),-   ethylenediaminetetracetic acid (EDTA),-   CH₃C(═NCH₂CH₂OH)CH₂C(O)N(CH₃)₂,-   CH₃C(═NCH₂CH₂OCH₂CH₂OH)CH₂C(O)N(CH₃)₂,-   CH₃C(═NH)CH₂C(O)CH₃,-   (CH₃CH₂)₂NC(═NH)N(CH₃CH₂)₂,-   HOOCCH₂N(CH₃)₂, and-   HOOCCH₂N(CH₃)CH₂COOH.

The metal chelating agent or mixture of chelating agents typicallycomprises about 0 to about 5.0% of the formulation. Typical metalchelating agent may be one of many such metal chelating agents known tothose skilled in the art including:

-   acetoacetamide;-   ammonium carbamate;-   ammonium pyrrolidinedithiocarbamate (APDC);-   dimethyl malonate;-   methyl acetoacetate;-   N-methyl acetoacetamide;-   2,4-pentanedione;-   1,1,1,5,5,5-hexafluoro-2,4-pentanedione H(hfac);-   2,2,6,6-tetramethyl-3,5-heptanedione H(thd);-   tetramethylammonium thiobenzoate;-   tetramethylammonium trifluoroacetate;-   tetramethylthiuram disulfide (TMTDS);-   trifluoracetic acid;-   lactic acid;-   ammonium lactate;-   malonic acid-   formic acid,-   acetic acid,-   propionic acid,-   gamma-butyrolactone,-   methyldiethanolammonium trifluoroacetate, and-   trifluoroacetic acid.

Several representative examples of formulations are:

Triethanolamine 4.5% Ammonium Fluoride 0.5% Water  95%

PMDETA 3.8-4.5% Ammonium Fluoride 0.5% 2,4-Pentanedione   1% Water  94-94.7%

TEA 1.7% PMDETA 1.5% TEAHF   2% Iminodiacetic Acid 0.4% AmmoniumBifluoride 0.5% Water 93.9% 

TEA 3.5% PMDETA 1.5% 2,4-Pentanedione 1.35%  Ammonium Fluoride 1.2%Water 92.45% 

TEA   7% PMDETA   3% 2,4-Pentanedione 2.7% Ammonium Fluoride 2.4% Water84.9% 

Wafers can be immersed in chemical solutions or chemicals can be appliedto the wafer surface by spray or through a brush scrubbing system. FIG.5 depicts a SEM representing the results obtained with a standardimmersion process. Specifically FIG. 5 depicts Tungsten plugs afteralumina slurry CMP and immersion in formula c for 10 min at 30° C.Furthermore, selectivity to exposed materials may be illustrated by etchrate data. FIG. 6 and table 3 illustrate the material etch rate oninterconnect materials including an electroplated copper film.

TABLE 3 Material Etch Rate, Å/min for 21° C. @ 30 min Copper ~1 TantalumNitride <0.1 Titanium <0.1 Titanium Nitride 1.0 Tungsten 0.2 TEOS 1.5BPSG 4.5

While the invention has been described herein with reference to specificfeatures, aspects, and embodiments, it will be appreciated that theinvention is not thus limited. The invention therefore maycorrespondingly embodied in a wide variety of compositions, withcorresponding variations of ingredients, and end-use applications. Theinvention therefore is to be understood as encompassing all suchvariations, modifications and alternative embodiments, within the spiritand scope of the invention as hereafter claimed.

1.-56. (canceled)
 57. A method of removing metal halide residue, metaloxide residue, or both from a semiconductor wafer, said methodcomprising cleaning the wafer by contacting same with a cleaningformulation, wherein said cleaning formulation comprises (i) a fluoridesource, (ii) at least one organic amine, (iii) a nitrogen-containingcarboxylic acid or an imine, (iv) water, and optionally at least onemetal chelating agent.
 58. The method of claim 57, wherein thenitrogen-containing carboxylic acid or imine is selected from the groupconsisting of: iminodiacetic acid (IDA), glycine,1,1,3,3-tetramethylguanidine (TMG), CH₃C(═NCH₂CH₂OH)CH₂C(O)N(CH₃)₂,CH₃C(═NCH₂CH₂OCH₂CH₂OH)CH₂C(O)N(CH₃)₂, CH₃C(═NH)CH₂C(O)CH₃,(CH₃CH₂)₂NC(═NH)N(CH₃CH₂)₂, HOOCCH₂N(CH₃)₂, and HOOCCH₂N(CH₃)CH₂COOH.59. The method of claim 57, wherein the wafer cleaning composition has apH greater than
 7. 60. The method of claim 57, wherein the amount ofnitrogen-containing carboxylic acid or imine is 0.1-40 weight percent,based on the total weight of the composition.
 61. The method of claim57, wherein the fluoride source comprises a fluoride species selectedfrom the group consisting of: any combination of ammonia gas or ammoniumhydroxide and hydrogen fluoride gas or hydrofluoric acid, ammoniumbifluoride, ammonium fluoride, triethanolammonium fluoride (TEAF),diglycolammonium fluoride (DGAF), tetramethylammonium fluoride (TMAF),methyldiethanolammonium fluoride (MDEAF), and triethylaminetris(hydrogen fluoride) (TREAT-HF).
 62. The method of claim 57, whereinthe amount of fluoride source is 1-35% weight percent, based on thetotal weight of the composition.
 63. The method of claim 57, wherein theorganic amine(s) comprise an amine(s) selected from the group consistingof: diglycolamine (DGA), methyldiethanolamine (MDEA),pentamethyldiethylenetriamine (PMDETA), triethanolamine (TEA),triethylenediamine (TEDA), hexamethylenetetramine,3,3-iminobis(N,N-dimethylpropylamine), monoethanolamine,2-(methylamino)ethanol, 4-(2-hydroxyethyl)morpholine,4-(3-aminopropyl)morpholine, and N,N-dimethyl-2-(2-aminoethoxyl)ethanol.64. The method of claim 57, wherein the amount of organic amine(s) is20-60% weight percent, based on the total weight of the composition. 65.The method of claim 57, wherein the amount of water is 20-50% weightpercent, based on the total weight of the composition.
 66. The method ofclaim 57, wherein the wafer cleaning formulation further comprises atleast one metal chelating agent selected from the group consisting of:acetoacetamide, ammonium carbamate, ammonium pyrrolidinedithiocarbamate(APDC), dimethyl malonate, methyl acetoacetate, N-methyl acetoacetamide,2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione H(hfac),2,2,6,6-tetrammethyl-3,5-heptanedione H(thd), tetramethylammoniumthiobenzoate, tetramethylammonium trifluoroacetate, tetramethylthiuramdisulfide (TMTDS), trifluoracetic acid, lactic acid, ammonium lactate,malonic acid, formic acid, acetic acid, propionic acid,gamma-butyrolactone, iminodiacetic acid, methyldiethanolammoniumtrifluoroacetate, and trifluoroacetic acid.
 67. The method of claim 66,wherein the amount of at least one metal chelating agent is 0-21% weightpercent, based on the total weight of the composition.
 68. The method ofclaim 57, wherein said fluoride source comprises a compound having thegeneral formula R₁R₂R₃R₄NF in which each of the R groups isindependently selected from hydrogen atoms, C₁-C₈ alkyl, aryl andalkenyl groups, and wherein said formulation includes a metal chelatingagent of the formula:X—CHR—Y in which R is either hydrogen, C₁-C₈ alkyl, aryl or alkenylgroup and X and Y are functional groups containing multiply bondedmoieties having electron-withdrawing properties.
 69. The method of claim67, wherein each of X and Y is independently selected from CONH₂,CONHR′, CN, NO₂, SOR′, and SO₂Z in which R′ is C₁-C₈ alkyl and Z ishydrogen, halo, or C₁-C₈ alkyl.
 70. The method of claim 57, wherein thenitrogen-containing carboxylic or imine comprises iminodiacetic acid.